Approximation Theory and Special Functions

Oktay Duman is a faculty member at TOBB Economics and Technology University, Ankara, Türkiye. He currently serves as the Dean of the Faculty of Arts and Sciences and as the Head of the Department of Mathematics at the same institution. He earned his PhD in Mathematics from Ankara University, Türkiye, in 2003, and he had a visiting period at the University of Central Florida, USA, in 2016. In recognition of his contributions to approximation theory, he was elected as a Full Member of the Turkish Academy of Sciences in 2020.Esra Erkus-Duman is a Full Professor at Ankara University, Türkiye, with a PhD and a Master's degree in Mathematics obtained in 2005 from the same university. Previously, she held positions as an Associate Professor (2010-2017) and an Assistant Professor (2007-2010) at Gazi University, Türkiye. In 2015, she was a visiting professor at the University of Central Florida, USA. Her research focuses on special functions.

• Interpolating projections in Fréchet algebras.- Trigonometric Background Multivariate Smooth Poisson-Cauchy Singular Integrals Approximation.- Asymptotic and quantitative results of Neural Network operators that employ wavelets.- Genuine Bernstein-Durrmeyer type operators preserving 1 and x^j (II).- Korovkin-type approximation theorems for functions with the help of Istatistical convergence.- Fractional Approximation of Time Separating Stochastic Processes by Neural Networks of Compact Support.- Some Results of Korovkin Type For Nonlinear Operators.- Approximation Properties of Generalized Q-Favard-Sz´asz-Mirakjan Operators of Max-Product Kind.- Riemann-Liouville Type Fractional Generalized $\lambda-$Bernstein-Kantorovich Operators.- Parametric Extensions of a Certain Family of Bernstein-Type Rational Functions.- Stability Analysis of a SAIR Epidemic Model with Logistic Growth in Susceptible Compartment.- Numerical Solution and Effective Error Estimation for a Mixed Problem for the Laplace Equation.- On Some Comparison of Multi-step Multi-derivative Methods and Its Application to Solve the Volterra Integro-Differential Equations.- Existence and Uniqueness of strong Solution of the Time fractional integro differential equation with integral boundary conditions.- The New Numerical Solutions of the Atangana-Baleanu Fractional Benney Equation.- A New Dual-phase Hybrid Variable Selection Method in High-Dimensional Data.- Certain New Integral Formulas Involving the Generalized Multi-index Bessel Functions.- Lower Bounds for Extremal Polynomials.- General Families of Cosine and Sine Appell Polynomials.- Some properties of Frobenius-Sigmoid polynomials.- The Appell-Fibonacci Polynomials.- On Bivariate Jacobi Konhauser Polynomials.- The Multivariable-Multiparameter generalized Cesaro polynomials and the generalized Lauricella functions.- The Difference Equation of Meijier’s G-function.- The generalized finite bivariate biorthogonal M - Jacobi polynomials.- Probabilistic new type degenerate Bell polynomials of the second kind associated with random variables.- Fuzzy Parameterized CR-Fuzzy Soft Sets and Some Set Operations.- A Modified Similarity Measure for Continuous Function Valued Intuitionistic Fuzzy Sets and An Application on Classification.- Energy spectrum for Scarf-Grosche potential.- Some Inequalities for Riesz Potential on Homogeneous Variable Exponent Herz-Morrey-Hardy Spaces.- Fixed Point Results of Contractive Mappings Under Simulation Function in Metric Spaces.- Completely Monotone Invariance of Smoothing via Central Vector Lattice Differences.- Spectrum Density Estimation of Sample Covariance Matrices with Correlated Entries.- Modelling of Count Data in Circular Statistics.- Reconstruction of the North Atlantic Double-gyre Circulation with Genetic Programming.- On Normal Subgroups of General Linear Groups of Certain $C^*$-Algebras.